Colligative Freezing-Point Depression, Boiling Elevation & Osmotic Pressure Calculator

Evaluate ΔTf, ΔTb, and osmotic pressure using the van ’t Hoff dissociation factor i.

Aqueous Freezing-Point Depression (−ΔT_f)
-5.58 °C
New Boiling Point (100 + ΔT_b) 101.54 °C
Osmotic Pressure (Π) 73.4 atm
Effective Osmolality 3 Osm/kg
Inputs
mol/kg
Solute concentration in moles per kg of water (molality m).
i
Van ’t Hoff ion dissociation factor i (1 glucose, 2 NaCl, 3 CaCl₂).
K
Solution temperature in Kelvin for osmotic pressure.
Results & Graph
Aqueous Freezing-Point Depression (−ΔT_f)
-5.58 °C
New Boiling Point (100 + ΔT_b)
101.54 °C
Osmotic Pressure (Π)
73.4 atm
Effective Osmolality
3 Osm/kg

Aqueous Freezing-Point Depression (−ΔT_f)

Graph 1 • Molality Mol Kg Sensitivity Recalculates the domain equation across 50% to 150% of the primary input while holding other parameters constant.
-8.4 °C -3.6 °C 1.1 °C 50%: -2.79 °C -2.8 50% 75%: -4.19 °C -4.2 75% 100%: -5.58 °C -5.6 100% 125%: -6.97 °C -7.0 125% 150%: -8.37 °C -8.4 150%
Graph 2 • Primary & Supporting Metric Comparison Compares the primary output alongside supporting domain benchmarks.
Aqueous Freezing-Point Depression (−ΔT_f) -5.58 °C New Boiling Point (100 + ΔT_b) 101.54 °C Osmotic Pressure (Π) 73.4 atm Effective Osmolality 3 Osm/kg
Graph 3 • Exact Output Table & Units Displays each calculated output in its exact domain unit.
Aqueous Freezing-Point Depression (−ΔT_f)-5.58 °CNew Boiling Point (100 + ΔT_b)101.54 °COsmotic Pressure (Π)73.4 atmEffective Osmolality3 Osm/kg
Summary: An aqueous solution of 1.5 mol/kg (van ’t Hoff i=2, 3 Osm/kg) freezes at -5.58°C, boils at 101.54°C, and exerts 73.4 atm osmotic pressure.
Summary: An aqueous solution of 1.5 mol/kg (van ’t Hoff i=2, 3 Osm/kg) freezes at -5.58°C, boils at 101.54°C, and exerts 73.4 atm osmotic pressure.
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Formula & Mathematical Methodology: Colligative Properties Reference Equation

ΔTf = i × Kf × m
ΔTb = i × Kb × m
Πatm = i × m × 0.082057 × TK
ΔT_f = i × K_f × m; ΔT_b = i × K_b × m; Π_atm = i × m × 0.082057 × T_K
  • molalityMolKg: Molality Mol Kg (mol/kg)
  • vantHoffFactorI: Vant Hoff Factor I (i)
  • temperatureKelvin: Temperature Kelvin (K)

Rounding: Laboratory and clinical equations retain full floating-point precision and round displayed results to 2 decimal places.

Worked Example: Reference Calculation: Colligative Properties

Evaluate ΔTf, ΔTb, and osmotic pressure using the van ’t Hoff dissociation factor i.

  1. Enter the reagent concentrations, assay readings, or clinical laboratory parameters.
  2. Compute the standard formula: ΔT_f = i × K_f × m; ΔT_b = i × K_b × m; Π_atm = i × m × 0.082057 × T_K.
  3. Review the primary result, supporting reference intervals, and 3 SVG visualizations.
Result: Evaluates Colligative Properties via ΔT_f = i × K_f × m; ΔT_b = i × K_b × m; Π_atm = i × m × 0.082057 × T_K.

Frequently Asked Questions

What formula is used by the Colligative Freezing-Point Depression, Boiling Elevation & Osmotic Pressure Calculator?

It computes ΔT_f = i × K_f × m; ΔT_b = i × K_b × m; Π_atm = i × m × 0.082057 × T_K and plots three custom SVG graphs showing parameter sensitivity and component breakdowns.

Can I compare different reagent dilutions or lab scenarios side by side?

Yes. Use the "Compare (0/3)" button to pin up to 3 scenarios side by side.

Are entered values stored on any server?

No. Every calculation runs 100% locally in your browser.

Science & Engineering · Analytical Chemistry & Lab Bench

Colligative Freezing-Point Depression, Boiling Elevation & Osmotic Pressure Calculator: inputs, method, and how to read the result

Evaluate ΔTf, ΔTb, and osmotic pressure using the van ’t Hoff dissociation factor i.

Choose inputs for the case you are checking

The defaults are illustrative. Replace them with values for your case and keep the units shown beside each field.

  • Molality Mol Kg: Solute concentration in moles per kg of water (molality m).
  • Vant Hoff Factor I: Van ’t Hoff ion dissociation factor i (1 glucose, 2 NaCl, 3 CaCl₂).
  • Temperature Kelvin: Solution temperature in Kelvin for osmotic pressure.

What the calculation includes

With the default values shown, Aqueous Freezing-Point Depression (−ΔT_f) is -5.58 °C. The calculation follows Colligative Properties Reference Equation; the formula and variable definitions above show how the inputs combine.

One-input check: With the other defaults held constant, changing Molality Mol Kg from 1.5 mol/kg to 1.65 mol/kg changes Aqueous Freezing-Point Depression (−ΔT_f) from -5.58 °C to -6.14 °C. This is a comparison inside the calculator's stated model, not a prediction.

Where to use caution

  • Uses standard IUPAC atomic weights, 25°C (298.15 K) reference thermodynamics, and published clinical literature equations.
  • Educational and laboratory reference tool only; clinical scoring calculators do not replace professional medical judgment or institutional protocols.

Scope: IUPAC / NIH Laboratory & Clinical Reference Standard Check the assumptions and limitations against your situation before relying on the estimate.

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